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Ellenville, New York: A Classic Locality

December 11, 2007

By Hawkins, Michael

The origins of the mines in the Ellenville area, like so many of the mines of early America, have been lost in the fog of time. Local legends have the mines variously attributed to the Dutch, the Spanish (remnants of Ponce de Leon’s party searching for the fountain of youth), American Indians, or aliens in UFOs seeking to extract energy from the quartz crystals deep within the Shawangunk Mountains. Today, all that remains of the famous Ellenville mines are a few tailings piles, collapsed mine shafts, and broken-down building foundations, but during the glory years of the nineteenth century these mines produced the world-class specimens of quartz and chalcopyrite that reside in museums and private collections around the globe.

Location

The metallic sulfide veins in the Shawangunk Mountains in New York form a northeast-southwest-trending band from Port Jervis in the south toward Kingston in the north (fig. 1). Commercially, the most important workings were in Ellenville (Ulster County), Wurtsboro (Sullivan County), and Guymard (Orange County) with minor workings in Otisville (Orange County) and Spring Glen (Ulster County). The area also contains some small unnamed prospect pits. The mines near Ellenville produced the great majority of crystallized mineral specimens. The Delaware Aqueduct Tunnel, dug in the late 1930s and early 1940s for the New York City water supply, intersected ore veins near Shaft 2A in Warwarsing (Ulster County) (Bird 1944), and some specimens were recovered from the shafts and dumps. Noteworthy specimens from the other mines in this formation are very limited.

Geological Setting

The zinc-lead-copper veins that were mined in the Ellenville area are of hydrothermal origin and “were probably deposited from solutions evolved from connate brines” (Wilber et al. 1990). The veins occur in faults and fissures along a 20-mile section of the Shawangunk Mountains, a mountain ridge running from near Kingston, Ulster County, New York, to the Delaware Water Gap in Pennsylvania. The Shawangunks are of Middle Silurian age and represent a clastic wedge uplifted during the Taconic Orogeny (Epstein and Epstein 1972); they are composed primarily of orthoquartzitic conglomerates, sandstones, and graywackes interbedded with shales. The ore veins themselves are much younger and appear to be of Alleghanian age (about 260 million years ago) or younger (Dorobek 1989).

History

Records from the Dutch West India Corporation written from New Netherlands in 1644 contain the reference that “mines of copper and lead have been discovered in these mountains.” The “prospector and miner Claes de Ruyter told the directors that he had discovered copper and other minerals in a crystal mountain,” possibly in adjacent Pahaquarry, New Jersey (Newark Star-Ledger 1975). The “Old Mine Road,” alleged to be one of the oldest routes in America, ran 104 miles along the Shawangunks from the Hudson River to the Pahaquarry area, and it seems likely that early prospectors would have searched for additional ore deposits along its length.

We know that lead mining in the Ellenville area commenced prior to 1730 for “a road commissioner’s record in 1730 refers to ‘Anthony Rutgers and Company owners and proprietors of a lead mine near Nepenagh?’ ” (Terwilliger 1977). The mining activities from 1730 on are fairly well documented, with several small-scale mining efforts recorded in the Shawangunks through the late eighteenth and early nineteenth centuries.

The history of “modern” mining in Ellenville during the nineteenth century followed the typical pattern of boom and bust associated with so much of the mining in that period. A fairly sizable amount of ore was extracted from the mine, as evidenced by a report from mining geologist James T. Hodge to the president of the Ulster Mining Company, James Elnathan Smith, in 1852. The report states “it would not be far out of the way to count upon 100 tons of ore on the surface?this in addition to the 20 tons of galena sent to New York?: The copper ore is a pure quality of pyritous copper. One lot of about 9 tons is in the house ?and there are several tons more outside?mixed with clay” (Hodge 1852). “By October 1853 the mine had been extended 200 feet into the mountain with a shaft 90 feet deep. Two or three tons of copper were being removed daily?they smelted about 4,500 pounds of lead per day” (Hodge 1854) (fig. 2). Then, in spring 1854, the mine closed. Hodge reported in his latter years that the “men who controlled the mine were more interested in stock speculations, than in rendering the mine permanently productive” (Terwilliger 1977). The mine was reopened in 1862 by the Union Lead Mining Company and ran until 1866, probably to meet the need for lead during the Civil War.

Magnificent quartz crystals have been noted since the beginning of work at the mine, and “in the 1880′s much attention was paid in the [Ellenville] Journal to the exquisite examples which were being brought out?. When mining for zinc began in 1902 by the Ellenville Zinc Company some of the most beautiful were exhibited at the First National Bank there in 1903. Tiffany & Co. of New York City bought them and, among other places, exhibited them at the St. Louis Exposition in 1904″ (Ellenville Journal 1969).

Many of the finest specimens of chalcopyrite and quartz were recovered during the on-and-off “zinc” mining period of 1902-19 (fig. 3). A local superintendent at the mine, P. Edwin Clark, assembled a large collection of spectacular specimens during that period. He donated some of them to the New York State Museum (NYSM) in 1904. His entire collection was donated, by his estate, to the museum after his death in 1957.

The exact closing dates for the various mines are not clear, as various attempts were made to dewater and re-open the mines, but it appears the last attempts at the Ellenville mine were around 1919. The U.S. Bureau of Mines did some diamond drilling in the late 1940s in an attempt to locate strategic mineral reserves at the Shawangunk mine in Wurtsboro, and a little work was attempted there in 1961 by the Shawangunk Mining Company of Riverdale, New Jersey (Heusser 1977), but no ore mining has taken place anywhere in the Shawangunks since that time.

Mineralogy

The mineralogy of the deposits is fairly simple, consisting of the primary sulfides-chalcopyrite, sphalerite, galena, and pyrite- and the gangue mineral quartz. Molybdenite was reported (Gray 1953), but no verifiable specimens were located in the course of this study. However, a single credible specimen of wulfenite, a lead molybdate, listed from Ellenville was found in the collections at the Rensselaer Polytechnic Institute, so there may be molybdenum in the deposit.

Brookite is well represented in preserved specimens, but only one specimen of microscopic anatase crystals with brookite and quartz from the Ellenville mine exists in the NYSM collection. A second microscopic anatase crystal was discovered on a brookite specimen from the Wheatley collection at Union College during the investigations for this article. There are also reports of rutile, but no rutile specimens could be located in any known collection. A cobaltite-group mineral was reported (Wilbur 1990), and some old reports refer to cobalt in the ores of the mines, but no specimens of minerals containing cobalt could be located. Very small amounts of other minerals, such as anglesite, azurite, aurichalcite, calcite, cerussite, chalcocite, chlorite, covellite, gold, hematite, limonite, malachite, muscovite, siderite, and “wad,” occurred, but no specimens of any size or quality have been preserved. The following are descriptions of the minerals of interest to collectors.

Anatase, TiO2, was found, along with brookite, on a specimen from the P. Edwin Clark collection at the NYSM. Dozens of tiny, pale electric blue anatase crystals to 0.2 mm occur on this specimen. The crystals consist of a dominant primary tetragonal bipyramid {011}, heavily striated parallel to the equator and modified by minor faces of the secondary bipyramid {017} (fig. 4). The paragenesis of this particular specimen is anatase > quartz > brookite, indicating a shift in the conditions during crystallization.

Brookite, TiO^sup 2^, occurs as crystals to 1 cm on quartz. Goldschmidt’s Atlas der Krystallformen (1913) contains three drawings of Ellenville brookite crystals (fig. 5). Brookite occurred in the Ellenville mines and in the Delaware Aqueduct Tunnel. It has not been recorded from any of the other deposits, but that may have been the result of its being overlooked. Typical crystals are dark brown to black laths by reflected light, dominated by one lateral pinacoid bearing heavy striations parallel to the long axis of the crystal, with minor development of one or two other pinacoids and one to several orthorhombic prisms and bipyramids. A drawing of an Ellenville brookite crystal in Dana’s seventh edition (1944) shows three pinacoids, five prisms, and three bipyramids. By transmitted light the crystals are transparent and honey-yellow to dark brown to reddish-brown, sometimes with hour-glass-shaped darker color zones (figs. 6-8).

Chalcopyrite, CuFeS2, was the chief ore of copper in all the mines in the Shawangunks. Euhedral crystals and crystal groups to 12 cm occur on quartz crystals and were recovered from the mining operations at the Ellenville (Ulster) mine from the mid-nineteenth century to the early twentieth century. Most of the chalcopyrite crystals were coated with a thin black layer of covellite (figs. 9 and 10). Bright, brassy crystals have probably been cleaned to remove this layer (fig. 14), although a few of the chalcopyrite crystals were recovered without the covellite coating (figs. 12 and 13). Goldschmidt’s Atlas der Krystallformen (1918) contains four drawings of chalcopyrite from Ellenville (fig. 11). The essential habit consists of the flat bisphenoid {118} and the steep bisphenoid {221}. Occasionally, smaller faces of the negative bisphenoid {118} and/or the tetragonal scalenohedron {3?6?16} are present as small corner bevels. Galena, PbS, was “abundant at the surface and is increasingly replaced by zincblende and chalcopyrite at depth” (Nason 1894). Crude octahedral crystals to 11 cm occur, but few specimens of aesthetic value seem to have existed or survived. Galena is sometimes found as microscopic metallic blebs inside transparent, colorless quartz crystals.

Pyrite, FeS2, was found in minor amounts in the ore veins, and crystals to 1 cm on large plates were recovered during the working of the cliffs above the Ellenville mine for riprap in the 1970s by the Army Corp of Engineers.

Sphalerite, ZnS, was the most abundant ore mineral in the mines of the Shawangunks. The few crystallized specimens that have been preserved consist of patches of parallel growth of small, reddish- brown, tetrahedral crystals on quartz. A fine display specimen with larger, more complex crystals has been preserved (fig. 15).

Quartz, SiO2, crystals lined the fractures and fissures of the mines and are the primary reason for Ellenville’s status as a classic New York State locality. Colorless, transparent quartz crystals form exquisite specimens (figs. 16, 10, and 13), many with blue-black covellite-coated chalcopyrite crystals and less frequently with sphalerite crystals or brookite crystals. Large clusters of more equant quartz crystals (fig. 18) resemble Herkimer “diamond” clusters in habit and structure but are not as transparent. Some quartz crystals are white and translucent (figs. 17 and 19) and are sometimes stained brown by goethite. Quartz clusters to a meter across were recovered, and single crystals to 20 cm are preserved at the NYSM. Also of interest to collectors are the smaller “floater” specimens of quartz that appear to have been sheared off by tectonic activity and then healed with vicinal faces. A few of these also show partial skeletal development, and a particularly good example is shown in Goldschmidt (1922) (fig. 20). These crystals were relatively common in the mine dumps in Ellenville. They range from colorless through white to gray, brown, and reddish-brown. One of these floater crystals was collected by Leonard Morgan in the 1940s and is the only known Japan-law quartz twin from New York State (fig. 22). Clusters of quartz crystals, some stained brown by iron oxides with green interiors from included chlorite, were found at Otisville (fig. 21).

Wulfenite, PbMoO4, was preserved as a single specimen in the Rensselaer Polytechnic Institute collection and is now in the NYSM collection (fig. 23). The tabular crystals have a basal pinacoid, tetragonal bipyramid, and tetragonal prism.

Specimen Attribution

There is some confusion over locality names in the literature for specific mines in the Ellenville area. The “original” mine, as described by Mather (1843) and others, appears at the upper left on the 1853 map (fig. 2). It is shown as the “old mine”; it has also been called the Spanish mine or the Sun-Ray Tunnel. The “modern” workings, where the great majority of the mineral specimens labeled Ellenville were collected, are shown at the far right on the 1853 map as shaft no. 1 and shaft no. 2. These workings were referred to, at various times, as the Ulster mine, the Union mine, the Ellenville mine, and the Ellenville zinc mine. The name Ulster mine was also used for a small mine in nearby Spring Glen. That mine was also known as the Red Bridge mine, the Spring Glen mine, and the Horseshoe mine. It was quite small, but quartz crystals from this location sometimes appear, usually labeled as the Red Bridge mine.

ACKNOWLEDGMENTS

I thank Patricia Christian of the Ellenville Public Library and Museum for searching out and copying articles and photos for this article; Ray Decker, Frank Ketcham, and Frank Mappes for helping with fieldwork in the Otisville area; and especially Dr. Steven C. Chamberlain for upgrading, revising, and reviewing this paper.

REFERENCES

Bird, P. H. 1944. Crystal-lined cavity in Shawangunk Grit. Delaware Water Supply News, 6 (121): 563.

Dorobek, S. 1989. Migration of fluids through the Silurian- Devonian Helderberg Group during late Paleozoic deformation. Tectonophysics 159:25-45.

Ellenville Journal. 1969. Some attempts at mining in the Town of Warwarsing, 12/11/1969. Ellenville, NY.

Epstein, J. B., and A. G. Epstein. 1972. The Shawangunk Formation (Upper Ordovician(?) to Middle Silurian) in eastern Pennsylvania. U.S. Geological Survey professional paper 744.

Gray, C. 1953. The lead-zinc ores of the Shawangunk Mountains district. Unpublished Ph.D. thesis, Columbia University.

Goldschmidt, V. 1913. Atlas der Krystallformen. Facsimile reprint of plates and text, vol. 1, by the Rochester Mineralogical Symposium, Rochester, NY, 1986.

_____. 1918. Atlas der Krystallformen. Facsimile reprint of plates and text, vol. 5, by the Rochester Mineralogical Symposium, Rochester, NY, 1986.

_____. 1922. Atlas der Krystallformen. Facsimile reprint of plates and text, vol. 7, by the Rochester Mineralogical Symposium, Rochester, NY, 1986.

Heusser, G. 1976. Legends and history and minerals of the Ellenville mines. Ellenville, NY: Privately published.

_____. 1977. Shawangunk Mountain lead-zinc deposit. Rocks & Minerals 52 (10): 515-20.

Hodge, J. T. 1852 and 1854. Report Ulster mine, Ellenville, Ulster County, New York. New York: D. Felt and Hosford, Stationers.

Mather, W. 1843. Geology of New York, part I. Albany, NY: Carroll and Cook.

Nason, F. L. 1894. The economic geology of Ulster County. New York State Museum annual report 47.

Newark Star Ledger. 1975. Pahaquarry mines laden with colonial lore, 1/28/1975. Newark, New Jersey.

Palache, C., H. Berman, and C. Frondel. 1944. The system of mineralogy. 7th ed. vol. 1. New York: John Wiley and Sons.

Terwilliger, K. 1977. Warwarsing: Where the streams wind. Ellenville, NY: Rondout Valley Publishing.

Wilber, J. S., F. E. Mutschler, J. D. Friedman, and R. E. Zartmann. 1990. New chemical, isotopic, and fluid inclusion data from the zinc-lead-copper veins, Shawangunk Mountains, New York. Economic Geology 85:182-96.

MICHAEL HAWKINS

3140 CEC

Research and Collections

New York State Museum

Albany, New York 12230

mhawkins@mail.nysed.gov

Michael Hawkins is the geology collections manager at the New York State Museum.

Copyright Heldref Publications Nov/Dec 2007

(c) 2007 Rocks and Minerals. Provided by ProQuest Information and Learning. All rights Reserved.




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